Fredericksburg is a census-designated place (CDP) in Bethel Township, Lebanon County, Pennsylvania, United States. The population was 987 at the 2000 census. Fredericksburg was originally called Stumptown after a disreputable settler named Frederick Stump, who founded the town in 1755, and reportedly massacred an encampment of ten inebriated Indians one winter and sent their bodies down the Susquehanna. Fredericksburg was the birthplace of Clayton Mark in 1858. Clayton Mark, the prominent steel magnate, was the founder of the planned worker community of Marktown.